New yz490 and Question

[hancadam]

I have a new YZ490 that I have a question about. The top end seems to have a knock to it. I cannot feel it on the block, but it sounds loud. I couldn't find anything rattling that may be causing it. The bike runs awesome, and is in great shape. The bottom end bearings where replaced by Yamaha about a year ago. Any insight on this would be greatly appreciated. It may be normal. I found a you tube video that sounded similar, but I don't remember my old 490 doing this though. Here are some pics:


http://img291.imageshack.us/img291/7879/blue11uj6.jpg (http://imageshack.us)

http://img186.imageshack.us/img186/9383/blue22ls8.jpg (http://imageshack.us)

[krizo88]

I think its normal. My 490 made alot of noise too. I even went as far as rebuilding it, and it still made noise. So i wouldnt worry about it. Nice bike love the 490's. Is that a 5 speed?

[Bryan Raffa]

air cooled + long cooling fins on the jug give it that sound.. I put some rubber gas line in between the fins .. it helps quiet it down some..anything done to the head? could be pre detonating from cheep gas.....

Nice Bike!:drool:

[evand]

im witht raffa could be spark knock?


but man that bike is clean as they come:beer

[hancadam]

I normally run 103 octane in it, but have been out of additive. I have 93 in it now. The head and carb have had a lot of work done to them. I bought it from a guy who builds nothing but 490's. And yes, its a 5 speed.

Thanks for the comments!!

[hancadam]

I love it, but it intimidates me pretty bad. It is brutally fast. My old 490 was a 4 speed but would fly and this one is even faster. It makes my 250sx feel like a tank. My cousin actually bought this bike from the same guy I bought my original 490 from. He paid 1800 for it, and mainly rode it on the rode. He sold it to me for 1000. He just bought a brand new RMZ450. He said he still think the YZ is faster. I have starting it down to a science. I can normally start it with 3 kicks.

[cr480r]

That is a very nice looking bike... I wouldnt be real concerned with the noise... I think its just the nature of the air-cooled beasts....

[hancadam]

Thanks for the compliment. I am not too concerned about the noise now. The consensus seems to its normal. Anyone know what kind of power these bikes are putting out?

Thanks, Adam.

[Bryan Raffa]

so what year is it? 86 was 46-48hp

[hancadam]

Its a 86. Thats around what I found. I thought it would be more considering how fast they are.

[cody2]

thats one hell of a nice bike!

[Ryan.]

whats the top speed on one of those beasts?

[hancadam]

I have read 106 stock, but I don't know how acurate that is. I have never gotten close to toping it out. Its take off is faster than any street bike I have ever rode.

[krizo88]

man that bike is clean! Gotta love when you crack on it and your holding on for dear life. I want it....lol

[Ryan.]

I have read 106 stock, but I don't know how acurate that is. I have never gotten close to toping it out. Its take off is faster than any street bike I have ever rode.

is the 490 faster than the cr500?

[hancadam]

is the 490 faster than the cr500?

From what I have read it is. The only bike stock that was faster than an 5 speed 490 from the big 4 was the kx500. That is strictly from what I read so not sure if it is true. I haven't rode either the honda or kawa. To me when where talking this kinda power it doesn't matter. I could never ride this bike to its max. I am already talking to the wife about a smaller bike. Don't get me wrong, I love the YZ, I just want something more civil. Its a fun bike to just take out every now and then. My 250sx is still my main ride.

[hancadam]

is the 490 faster than the cr500?

I belive the Maico 500 was faster also. Not sure though.

[cr480r]

is the 490 faster than the cr500?

not after the first corner...

[hancadam]

LOL, I am sure thats true. The suspension on these are crazy. I was really lucky to get this bike. Its shock has been rebuilt and had carb and head work. All that is bad on these bikes stock has been corrected I think. It is jetted correctly, the cylinder pinch has been corrected, and pinging is under control.

[lndy650]

ive owned a cr500 and a rm500 and ive rode a kx500 and a yz490...my rm500 is a 4 speed and ive never felt anything accelerate so fast in my life it tops out at about 100 id say the yz 490 was better than the kx and the cr though

[lndy650]

as for ther sound does it do it only when its cold? the pistons in big 2 strokes have a large clearance and when they are cold they slap the cylinder pretty bad til they warm up

[hancadam]

It seems to do it all the time. I never noticed it until I rode it in m yard with no helmet. My old one may have done the same, but I never rode it without a helmet. I have never rode a RM500. I think any 2 stroke 500cc will be insane. I use to think my 200x's where fast.

[lndy650]

ya i remember my first 200x i thought it had so much power!:lol:

[Charles Ford]

hey I'm getting a rolling blaster with out the motor this week and would to stuff a YZ 490 into it for mudding and climbing some hills. has anyone rode one or know of anyone with some parts like a YZ 490 motor,exhaust,carb, air box.?? I built my dream bike it was a 400ex frame with a XR-650L motor stuffed into it. I called it my ( TRX650EX KONG ) so I don't think this will be bad as I did that one for around $800.00 and it was going good until I rode a raptor 660. let me know if you can help. charliekat@oh.rr.com

my 98 grizzly 4x4 lost spark and need some help with that like a manual, stator, coil, cdi box ,??

Thanks Chas